Cannot build while running project in 5.4.2

General Issues and Bug Reporting
,
1

Severity Code Description Project File Line Suppression State Details
Error MSB3073 The command ““C:\Program Files\Epic Games\UE_5.4\Engine\Build\BatchFiles\Build.bat” AnimOfficialEditor Win64 Development -Project=“C:\Users\New\Documents\GitHub\AnimOfficial\AnimOfficial.uproject” -WaitMutex -FromMsBuild -architecture=x64” exited with code 6. AnimOfficial C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Microsoft\VC\v170\Microsoft.MakeFile.Targets 44

I get this error doing the follow:

  • Create new 3rd person project
  • Create create character base class (to test)
  • Close Visual Studio and Unreal Engine
  • Open Visual Studio and build project successfully
  • Launch Unreal Engine project from Visual Studio
    At this point I can still build from Visual Studio with it launched and it builds fine, however:
  • Make any edits to code in Visual Studio and try to build
  • Get the above error

I have visual studio integration tool installed and as you can see I’m using the latest version of Visual Studio 2022. It’s always worked in previous engine versions but for some reason it’s just popping errors now and I need to close Unreal Engine down before being able to recompile.

2

Check the usual culprit => Live Coding.
Try turning it off. Then save (so it remains unchecked in the project).
Now you should be able to build with the running project, no need to even restart.